[dvblast-devel] [PATCH] Improved preserve original TS ID

[Marian Ďurkovič]

Hi Andy,

On Tue, 29 Sep 2009 20:23:46 +0100, Andy Gatward wrote    
> Attached is an improved patch for preserving the original TS ID, based on
> Marian’s work.  A new CLI switch has been added, -T, which enables this 
> feature.  Not all users will want this feature enabled. 

  I was always wondering what are the reasons for rewriting TSID. Do you need to
have it unique for each IP stream for some administrative or technical reason?
Anyway, if this is the goal, then rewriting TSID with SID does not actually
help. There are multiple transponders using the same SID numbering scheme, so I
definitely have multiple IP streams using the same SID. When the original TSID
is preserved, at least the triplet {ONID, TSID, SID} is always unique. However,
when SID is copied to TSID, the difference is lost.

  Another reason for keeping the original TSID is the common approach of
detecting EIT specifics/brokeness by looking at {ONID, TSID} tuples. If TSID is
preserved, we can use the same approach regardless of stream delivery method
(i.e. what already works for DVB-S/C/T will also for for MPEG-TS over RTP). 

  Thus I believe that keeping the original TSID has clear benefits and therefore
I haven't made it optional in my patch. But if there are other requirements, we
should certainly go for a new CLI switch - however the open questions are what
should be the default and whether rewriting TSID with SID satisfies the intended
purpose.


    With kind regards,

          M.